The present invention relates to the field of mass storage devices. More particularly, this invention relates to an inertial latch in a disc drive.
One key component of any computer system is a device to store data. Computer systems have many different places where data can be stored. One common place for storing massive amounts of data in a computer system is on a disc drive. The most basic parts of a disc drive are a disc that is rotated, an actuator that moves a transducer to various locations over the disc, and electrical circuitry that is used to write and read data to and from the disc. The disc drive also includes circuitry for encoding data so that it can be successfully retrieved and written to the disc surface. A microprocessor controls most of the operations of the disc drive as well as passing the data back to the requesting computer and taking data from a requesting computer for storing to the disc.
The transducer is typically placed on a small ceramic block, also referred to as a slider, that is aerodynamically designed so that it flies over the disc. The slider is passed over the disc in a transducing relationship with the disc. Most sliders have an air-bearing surface (xe2x80x9cABSxe2x80x9d) which includes rails and a cavity between the rails. When the disc rotates, air is dragged between the rails and the disc surface causing pressure, which forces the head away from the disc. At the same time, the air rushing past the cavity or depression in the air bearing surface produces a negative pressure area. The negative pressure or suction counteracts the pressure produced at the rails. The slider is also attached to a load spring which produces a force on the slider directed toward the disc surface. The various forces equilibrate so the slider flies over the surface of the disc at a particular desired fly height. The fly height is the distance between the disc surface and the transducing head, which is typically the thickness of the air lubrication film. This film eliminates the friction and resulting wear that would occur if the transducing head and disc were in mechanical contact during disc rotation. In some disc drives, the slider passes through a layer of lubricant rather than flying over the surface of the disc.
Information representative of data is stored on the surface of the storage disc. Disc drive systems read and write information stored on tracks on storage discs. Transducers, in the form of read/write heads attached to the sliders, located on both sides of the storage disc, read and write information on the storage discs when the transducers are accurately positioned over one of the designated tracks on the surface of the storage disc. The transducer is also said to be moved to a target track. As the storage disc spins and the read/write head is accurately positioned above a target track, the read/write head can store data onto a track by writing information representative of data onto the storage disc. Similarly, reading data on a storage disc is accomplished by positioning the read/write head above a target track and reading the stored material on the storage disc. To write on or read from different tracks, the read/write head is moved radially across the tracks to a selected target track. The data is divided or grouped together on the tracks. In some disc drives, the tracks are a multiplicity of concentric circular tracks. In other disc drives, a continuous spiral is one track on one side of a disc drive. Servo feedback information is used to accurately locate the transducer. The actuator assembly is moved to the required position and held very accurately during a read or write operation using the servo information.
When the disc drive is not operating the actuator assembly is rotated away from and parked in a parking area. Because of the adverse consequences if the actuator contacts or impacts the data region of the disc, disc drives that park the actuator typically have some type of actuator lock to prevent the actuator from moving the carrier toward the data region of the disc in the event of external shock. Passive magnetic or spring locks apply restraining forces that are overcome when the drive is turned on and the actuator is activated. Passive locks are subject to failure in the presence of a sudden external force, the solenoid locks are unreliable, and inertial rotary locks have been found to be inoperable in the presence of an external force that causes the parked actuator to move into its crash stop.
One such inertial lock is shown in U.S. Pat. No. 5,448,436 assigned to IBM, which discloses an inertial latch that attempts to equate the frequency of bouncing of the actuator and the latch. However, this lock is subject to problems with secondary bouncing. During the primary latch-actuator engagement the latch tends to bounce off the actuator. The latch must then consistently reengage the actuator on secondary latch-actuator engagements. However, the latch sometimes fails to engage the actuator on secondary engagements allowing the actuator to damage the disc drive.
What is needed is a disc drive with a inertial lock that overcomes bouncing during latch-actuator engagement, particularly secondary latch bouncing.
The present invention includes an inertial latch that reduces the likelihood of damage due to secondary bouncing of the latch off of the actuator.
The present invention includes an information system including a disc drive having an inertial lock having a latching mechanism including a latch and a latch receiver. The latch receiver is located on the latch end of an actuator. The latching mechanism has a plurality of mating surfaces that engage between the latch and the latch receiver. The plurality of mating surfaces are located on the latch or the latch receiver.
The disc drive may include a latching mechanism with a plurality of teeth defining mating surfaces. The plurality of teeth may define a plurality of notches and opposed pairs of mating surfaces. The opposed pairs of mating surfaces may have a first mating surface and a second mating surface. The latching mechanism may have a latch point with opposed sides having a first opposed side and a second opposed side. The first mating surface may be engagable with the first opposed side and the second mating surface may be engagable with the second opposed side.
The present invention provides an inertial latch that reduces the likelihood of damage due to secondary bouncing of the latch off of the actuator. In addition, the present invention provides better reliability, with fewer failures. The present invention provides-better shock resistance and reduces stiction.